More than 20 years after the advent of balloon angioplasty, restenosis remains a major health care cost burden. Success in animal trials and treatments of other non-malignant lesions using radiotherapy has established a new branch of medical science, intravascular brachytherapy (IVB) in treating restenosis. In little over six years since the first application, there are more than half a million operations a year in USA alone, worldwide the number is over a million. Successful treatment results will depend critically on the proper delivery of optimum radiation dose to the vascular site. Radioactivity strength and uniformity of the WB sources used are of primary concern. This program takes a well-demonstrated radiation detection technology, the storage photostimulable phosphor (SPP) imager, and couples it to an innovative imaging approach for the characterization of IVB sources. The final product is a fast, accurate and low-cost 3-dimensional imaging system to map the radioactivity profile of a minuscule IVB seed source. A portable, non-electronic type pin-hole camera with a 360 degrees panoramic view which uses a SPP imager as film will be constructed to map radiation field of gamma-emitting IVB sources. For gamma-emitting as well as for gamma-emitting IVB sources a device that effectively wraps a SPP imager around an IVB source will be designed and constructed. A SPP image can provide a spatial resolution as fine as 25 microm and is more than 10/7 times sensitive than conventional radiochromic dye or fluorescence film. PROPOSED COMMERCIAL APPLICATION: The proposed radiation imaging technique will provide IVB manufacturers and practitioners a fast, accurate and low-cost mean to acquire the critical information on IVB source strength and uniformity. This technology is equally applicable in the characterization of other types of radioactive sources for medical use, including brachytherapy sources in general. We anticipate that the IVB field will continue its fast pace of growth and so will the demand for measuring technologies.